Re: Deprecating RULES

On 15 October 2012 00:30, Greg Stark <stark@mit.edu> wrote:
> On Sun, Oct 14, 2012 at 9:30 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>> On 12 October 2012 19:48, Greg Stark <stark@mit.edu> wrote:
>>> On Fri, Oct 12, 2012 at 7:55 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>>>> AFAICS all RULEs can be re-expressed as Triggers or Views.
>>>
>>> This is a bizarre discussion. Firstly this isn't even close to true.
>>> The whole source of people's discontentment is that triggers are *not*
>>> equivalent to rules. If they were then they wouldn't be so upset.
>>
>> This may be a confusion on the point of equivalence; clearly the
>> features work differently.
>>
>> I'm not aware of any rule that can't be rewritten as a trigger or a
>> view. Please can anyone show me some examples of those?
>
> Huh? The one thing we currently use rules for, implementing views,
> couldn't be done in triggers.

Yes, obviously....

> In general if your source table is empty
> then there's *nothing* you could cause to happen with triggers because
> no triggers will fire.

Before statement triggers will fire.


Please can anyone show me the SQL for a rule that cannot be written as
a view or a trigger? I do not believe such a thing exists and I will
provide free beer to the first person that can prove me wrong.

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services